In recent years, in order to achieve high breakdown voltage, low loss, use under a high temperature environment, and the like in a semiconductor device such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), silicon carbide has begun to be adopted as a material constituting a semiconductor device. Silicon carbide is a wide bandgap semiconductor having a band gap larger than that of silicon, which has been conventionally widely used as a material constituting a semiconductor device. Therefore, by adopting silicon carbide as a material constituting a semiconductor device, the semiconductor device can achieve high breakdown voltage, reduced on resistance, and the like. Moreover, a semiconductor device adopting silicon carbide as its material also has an advantage that its characteristics are less likely to be deteriorated when it is used under the high temperature environment, when compared with a semiconductor device adopting silicon as its material.
Japanese National Patent Publication No. 2000-509559 (PTD 1) discloses a silicon carbide field effect transistor having a gate trench. The silicon carbide field effect transistor has a highly concentrated p-region provided near a bottom portion of the gate trench, and the highly concentrated p-region is connected to a p-body region.